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East Alligator district centre water supply assessment : Kakadu National Park



East Alligator district centre water supply assessment : Kakadu National Park

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D . Pidsley


Jamieson, M.; Pidsley, D.; Paiva, Jerome


E-Publications; E-Books; PublicationNT; Technical Report ; 26/1991




Made available via the Publications (Legal Deposit) Act 2004 (NT).






Water-supply -- Northern Territory -- Kakadu National Park; Groundwater -- Northern Territory -- Kakadu National Park; Kakadu National Park (N.T.)

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Power and Water Authority

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Technical Report ; 26/1991


1 v. : ill., maps ; 30 cm.

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Technical Report WRD91026 Viewed at 15:07:48 on 29/07/2010 Page 24 of 107. constituents of water, others for the presence of heavy metals, and others for the bacteriological quality of the water. In addition to these tests, samples were taken for the purpose of this report in December 1990 and analysed for chemical. and bacteriological qt;.ali ty. The results of these analyses are summarised in Appendix 2. 2.4.2 Results of Chemical Analysis The ground water ;iUpply to East Alligator is acidic and of low hardness and low alkalinity. Typical pH of this water is in the range 4-6, with hardness (as CaC03) less than 20 mg/I, and Alkalinity (as CaC03) less than 20 mg/L also. The Total Dissolved Solids is usually less than 50 mg/L. Iron levels found in some samples is higher than the NHMRC recommended limit of 0.3 mg/L (Reference 4). This is probably due to the following two reasons. For samples taken water has been airlifted and will give an level of iron concentration in the water. during drillin9 the unrealistically high In other samples the iron concentration is high due to the corrosion of pipework, fittings, and/or storage tanks. These high iron levels are not present in the groundwater source. The pH of the samples is also outside the NHMRC guideline 6.5 to 8.5 (Reference 4). This limit has been set only for the control of corrosion and incrustation in the distribution system, and is not directly heal th related. l'esting for heavy metals has not shown the presence of any harmful concentrations of these constituents in the ground water supply. 2.4. 3 Biological Analvsis The purpose of biological monitoring of a water supply is to search for the pre.3ence of harmful The presence of organisms such micro organisms in the water. as ooliforms indicates that contamination of 1:he water supply may have taken place. The presence of E.coli. or faecal streptococci in a water is a more positive indicator of faecal pollution of the water, and hence there is a possibi.lity of pathogenic organisms being present in the water. TablE's showing the results of testing for these organisms in the water system at East Alligator are shown in Appendix 2. 005MJ